There has been conventionally known a wire circuit board in which a conductive layer is formed on a first insulation layer, a second insulation layer is formed on the first insulation layer and the conductive layer, and openings are formed in the first insulation layer and the second insulation layer at the same position in the conductive layer, so that a terminal portion in which a front surface and a rear surface of the conductive layer are exposed is formed (see JP2003-31915A). A terminal in which the front surface and the rear surface of the conductive layer are exposed is referred to as “flying lead”. In the flying lead portion, since both of the surfaces of the conductive layer are exposed, ultrasonic waves are easily transmitted upon an ultrasonic bonding with a terminal portion of an external circuit board. Thus, the flying lead portion is suited for an ultrasonic vibration bonding. On the other hand, since the flying lead portion is poor in physical strength, there is a problem in that breaking of wire is likely to occur, because of a stress concentrated in the conductive layer.
In order to prevent such a problem, attempts have been conventionally made to acquire the strength of the conductive layer at the flying lead portion, so as to effectively prevent breaking of the conductive layer. For example, in JP2003-31915A, at an intersection point where an end periphery of the opening and the conductive layer intersect with each other, there is formed a reinforcement part for reinforcing the conductive layer along the end periphery of the opening.